Ya it sounds like an air leak, try this to make sure
http://www.rchobbies.org/engine-tuning.htm

as for the fuel on the ground, it's most likely oil, not fuel. This is a good sign meaning there is plenty of oil to lubracate your engine. This is normal because you always run rich during break in.

once break in is done you can lean out your engine to get better perforamnce.
This is for the savage and t-maxx, but is the same for all nitro engines

http://www.youtube.com/watch?v=oSmMzpZM_As
http://www.youtube.com/watch?v=BJFsJ...elated&search=
http://www.youtube.com/watch?v=pEGjE...elated&search=

hope this helps!